Keyword: luminosity
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MOPLXGD1 The SuperKEKB Has Broken the World Record of the Luminosity injection, impedance, simulation, operation 1
 
  • Y. Funakoshi, T. Abe, K. Akai, Y. Arimoto, K. Egawa, S. Enomoto, H. Fukuma, K. Furukawa, N. Iida, H. Ikeda, T. Ishibashi, S.H. Iwabuchi, H. Kaji, T. Kamitani, T. Kawamoto, M. Kikuchi, T. Kobayashi, K. Kodama, H. Koiso, M. Masuzawa, K. Matsuoka, T. Mimashi, G. Mitsuka, F. Miyahara, T. Miyajima, T. Mori, A. Morita, S. Nakamura, T.T. Nakamura, K. Nakanishi, H.N. Nakayama, M. Nishiwaki, S. Ogasawara, K. Ohmi, Y. Ohnishi, N. Ohuchi, T. Okada, T. Oki, M.A. Rehman, Y. Seimiya, K. Shibata, Y. Suetsugu, H. Sugimoto, H. Sugimura, M. Tawada, S. Terui, M. Tobiyama, R. Ueki, X. Wang, K. Watanabe, S.I. Yoshimoto, T. Yoshimoto, D. Zhou, X. Zhou, Z.G. Zong
    KEK, Ibaraki, Japan
  • A. Natochii
    University of Hawaii, Honolulu,, USA
  • K. Oide
    CERN, Meyrin, Switzerland
  • R.J. Yang
    CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
  • K. Yoshihara
    Nagoya University, Nagoya, Aichi, Japan
 
  The SuperKEKB broke the world record of the luminosity in June 2020 in the Phase 3 operation. The luminosity has been increasing since then and the present highest luminosity is 4.65 x 1034 cm-2s-1 with βy* of 1 mm. The increase of the luminosity was brought with an application of crab waist, by increasing beam currents and by other improvements in the specific luminosity. In this paper, we describe what we have achieved and what we are struggling with. Finally, we mention a future plan briefly.  
slides icon Slides MOPLXGD1 [6.235 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD1  
About • Received ※ 10 June 2022 — Accepted ※ 08 July 2022 — Issue date ※ 10 July 2022  
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MOPOST005 The HL-LHC Project Gets Ready for Its Deployment operation, cavity, civil-engineering, collimation 50
 
  • M. Zerlauth, O.S. Brüning, B. Di Girolamo, P. Fessia, C. Gaignant, H. Garcia Gavela, E.H. Maclean, M. Modena, Th. Otto, L.J. Tavian, G. Vandoni
    CERN, Meyrin, Switzerland
 
  Following the successful completion of the second long shutdown (LS2), the Large Hadron Collider (LHC) is preparing for its final operational run before the majority of the High Luminosity Upgrade (HL-LHC) will be installed during the third Long Shutdown starting in 2026. The HL-LHC upgrade will enable a further tenfold increase in integrated luminosity delivered to the ATLAS and CMS experiments, starting by an upgrade of the machine protection, collimation and shielding systems in LS2, and followed by the deployment of novel key technologies, including Nb3Sn based insertion region magnets, cold powering by MgB2 superconducting links and integration of Nb crab-cavities to compensate the effects of a larger crossing angle. After a period of intensive R&D and prototyping, the project is now entering the phase of industrialization and series production for all main components. In this contribution, we provide an overview of the project status and plans for deployment and performance ramp-up. Progress on the validation of key technologies, status of prototypes and series production as well as the final integration studies for the HL equipment are summarized. These are accompanied by the imminent completion of major civil engineering work and the start of infrastructure installations. Initial operational experience will be gained at the Inner Triplet (IT) String, presently in assembly at CERN’s Superconducting Magnet Test Facility, which will enable a fully integrated test of the main magnets, powering, and protection systems in the actual HL-LHC insertion configuration.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST005  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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MOPOST009 EIC Crab Cavity Multipole Analysis and Their Effects on Dynamic Aperture cavity, multipole, dynamic-aperture, collider 66
 
  • Q. Wu, B.P. Xiao
    BNL, Upton, New York, USA
  • S.U. De Silva
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • Y. Luo
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Crab cavity is essential for retrieving the loss in luminosity due to the large crossing angle in the two colliding beam lines of the Electron Ion Collider (EIC). Due to the asymmetric design of the proton beam crab cavity, the fundamental mode consists of contributions from higher order multipoles. These multipole modes may change during fabrication and installation of the cavities, and therefore affect the local dynamic aperture. Thresholds for each order of the multipoles are applied to ensure dynamic aperture requirements at these crab cavities. In this paper, we analyzed the strength of the multipoles due to fabrication and installation accuracies, and set limitations to each procedure to maintain the dynamic aperture requirement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST009  
About • Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 10 July 2022
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MOPOST047 Determination of the Phase-Space Stability Border with Machine Learning Techniques dynamic-aperture, hadron, storage-ring, simulation 183
 
  • F.F. Van der Veken, R. Akbari, M.P. Bogaert, E. Fol, M. Giovannozzi, A.L. Lowyck, C.E. Montanari, W. Van Goethem
    CERN, Meyrin, Switzerland
 
  The dynamic aperture (DA) of a hadron accelerator is represented by the volume in phase space that exhibits bounded motion, where we disregard any disconnected parts that could be due to stable islands. To estimate DA in numerical simulations, it is customary to sample a set of initial conditions using a polar grid in the transverse planes, featuring a limited number of angles and using evenly distributed radial amplitudes. This method becomes very CPU intensive when detailed scans in 4D, and even more in higher dimensions, are used to compute the dynamic aperture. In this paper, a new method is presented, in which the border of the phase-space stable region is identified using a machine learning (ML) model. This allows one to optimise the computational time by taking the complex geometry of the phase space into account, using adaptive sampling to increase the density of initial conditions along the border of stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST047  
About • Received ※ 06 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022  
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MOPOMS042 Comparison Between Run 2 TID Measurements and FLUKA Simulations in the CERN LHC Tunnel of the Atlas Insertion Region radiation, simulation, operation, experiment 732
 
  • D. Prelipcean, K. Biłko, F. Cerutti, A. Ciccotelli, D. Di Francesca, R. García Alía, B. Humann, G. Lerner, D. Ricci, M. Sabaté-Gilarte
    CERN, Meyrin, Switzerland
  • B. Humann
    TU Vienna, Wien, Austria
 
  In this paper we present a systematic benchmark between the simulated and the measured data for the radiation monitors useful for Radiation to Electronics (R2E) studies at the Large Hadron Collider (LHC) at CERN. For this purpose, the radiation levels in the main LHC tunnel on the right side of the Interaction Point 1 (ATLAS detector) are simulated using the FLUKA Monte Carlo code and compared against Total Ionising Dose (TID) measurements performed with the Beam Loss Monitoring (BLM) system, and 180 m of Distributed Optical Fibre Radiation Sensor (DOFRS). Considering the complexity and the scale of the simulations as well as the variety of the LHC operational parameters, we find a generally good agreement between measured and simulated radiation levels, typically within a factor of 2 or better.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS042  
About • Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 26 June 2022 — Issue date ※ 09 July 2022
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TUPOST011 Simulation Studies of Intra-Train, Bunch-by-Bunch Feedback Systems at the International Linear Collider feedback, collider, ground-motion, linear-collider 861
 
  • R.L. Ramjiawan, D.R. Bett, P. Burrows, C. Perry
    JAI, Oxford, United Kingdom
  • D.R. Bett
    CERN, Meyrin, Switzerland
  • R.M. Bodenstein
    JLab, Newport News, Virginia, USA
  • G.B. Christian
    DLS, Oxfordshire, United Kingdom
 
  The International Linear Collider (ILC) is a proposed electron-positron collider targeting collision energies from 250 GeV to 1 TeV. With design luminosities of order 1034 cm2s-1, a beam-based, intra-train feedback system would be required near the Interaction Point (IP) to provide nanometre-level stabilisation of the beam overlap in the collisions. Here we present results from beam-tracking simulations of the 500 GeV ILC, including the impact of beam-trajectory imperfections on the luminosity, and the capability of the IP feedback system to compensate for them. Effects investigated include the position jitter introduced by the damping ring extraction kicker, short-range and long-range wakefields, and ground motion. The feedback system was shown to be able to correct for beam-beam offsets of up to 200 nm and stabilise the collision overlap to the nanometre level, within a few bunch crossings.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST011  
About • Received ※ 03 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 22 June 2022
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TUPOTK062 Settings for Improved Betatron Collimation in the First Run of the High Luminosity LHC collimation, dipole, collider, hadron 1366
 
  • B. Lindström, A. Abramov, R. Bruce, R. De Maria, P.D. Hermes, J. Molson, S. Redaelli, F.F. Van der Veken
    CERN, Meyrin, Switzerland
 
  Funding: This work was supported by the High Luminosity LHC project
The current betatron collimation system in the LHC is not optimized to absorb off-momentum particles scattered out from the primary collimators. The highest losses are concentrated in the downstream dispersion suppressor (DS). Given the increased beam intensity in the High Luminosity LHC (HL-LHC), there is concern that these losses could risk quenching the superconducting DS magnets. Consequently, a dedicated upgrade of the DS has been studied. However, at this stage, the deployment for the startup of the HL-LHC is uncertain due to delays in the availability of high-field magnets needed to integrate new collimators into the DS. In this paper, we describe the expected collimation setup for the first run of the HL-LHC and explore various techniques to improve the collimation cleaning. These include exploiting the asymmetric response of the two jaws of each primary collimator and adjusting the locally generated dispersion in the collimation insertion.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK062  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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WEIXGD1 EIC Beam Dynamics Challenges electron, hadron, polarization, cavity 1576
 
  • D. Xu, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, W.F. Bergan, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, K.A. Brown, Z.A. Conway, K.A. Drees, A.V. Fedotov, W. Fischer, C. Folz, D.M. Gassner, X. Gu, R.C. Gupta, Y. Hao, C. Hetzel, D. Holmes, H. Huang, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, G.J. Mahler, D. Marx, F. Méot, M.G. Minty, C. Montag, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, M.P. Sangroula, S. Seletskiy, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
  • S.V. Benson, B.R. Gamage, J.M. Grames, T.J. Michalski, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer
    JLab, Newport News, Virginia, USA
  • A. Blednykh, Y. Luo, B. Podobedov, S. Verdú-Andrés
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  • Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • E. Gianfelice-Wendt
    Fermilab, Batavia, Illinois, USA
  • G.H. Hoffstaetter, D. Sagan, J.E. Unger
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  The Electron Ion Collider aims to produce luminosities of 1034 cm-2s-1 . The machine will operate over a broad range of collision energies with highly polarized beams. The coexistence of highly radiative electrons and nonradiative ions produce a host of unique effects. Strong hadron cooling will be employed for the final factor of 3 luminosity boost.  
slides icon Slides WEIXGD1 [3.952 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXGD1  
About • Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 14 June 2022
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WEPOST003 Implications of the Upgrade II of LHCb on the LHC Insertion Region 8: From Energy Deposition Studies to Mitigation Strategies dipole, radiation, detector, experiment 1679
 
  • A. Ciccotelli
    The University of Manchester, Manchester, United Kingdom
  • R.B. Appleby
    UMAN, Manchester, United Kingdom
  • F. Butin, F. Cerutti, A. Ciccotelli, L.S. Esposito, B. Humann, M. Wehrle
    CERN, Meyrin, Switzerland
  • B. Humann
    TU Vienna, Wien, Austria
 
  Starting from LHC Run3, a first upgrade of the LHCb experiment (Upgrade I) will enable oeration with a significantly increased instantaneous luminosity in the LHC Insertion Region 8 (IR8), up to 2·1033/(cm2 s). Moreover, the proposed second upgrade of the LHCb experiment (Upgrade II) aims at increasing it by an extra factor 7.5 and collecting an integrated luminosity of 400/fb by the end of Run6. Such an ambitious goal poses challenges not only for the detector but also for the accelerator components. Monte Carlo simulations represent a valuable tool to predict the implications of the radiation impact on the machine, especially for future operational scenarios. A detailed IR8 model implemented by means of the FLUKA code is presented in this study. With such a model, we calculated the power density and dose distributions in the superconducting coils of the LHC final focusing quadrupoles (Q1-Q3) and separation dipole (D1) and we highlight a few critical issues calling for mitigation measures. Our study addresses also the recombination dipole (D2) and the suitability of the present TANb absorber, as well as the proton losses in the Dispersion Suppressor (DS) and their implications.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST003  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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WEPOST031 RHIC Polarized Proton Operation in Run 22 operation, polarization, proton, dipole 1765
 
  • V. Schoefer, E.C. Aschenauer, D. Bruno, K.A. Drees, W. Fischer, C.J. Gardner, K. Hock, H. Huang, R.L. Hulsart, C. Liu, Y. Luo, I. Marneris, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, J. Sandberg, W.B. Schmidke, F. Severino, T.C. Shrey, P. Thieberger, J.E. Tuozzolo, M. Valette, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno
    BNL, Upton, New York, USA
 
  The Relativistic Heavy Ion Collider (RHIC) Run 22 physics program consisted of collisions with vertically po- larized proton beams at a single collision point (the STAR detector). During initial startup of the collider, power out- ages damaged two of the coils in one of the RHIC helical dipole snake magnets used for polarization preservation in the Blue ring. That snake was reconfigured for use as a partial snake. We will outline some of the remediating mea- sures taken to maximize polarization transmission in this configuration. These measures included changing the col- liding beam energy from 255 GeV to 254.2 GeV to adjust the spin closed orbit at store and adjustment of the field in the other helical dipole in the Blue ring to improve injection spin matching. Later in the run, the primary motor gener- ator for the AGS (the injector to RHIC) failed and a lower voltage backup had to be used, resulting in a period of lower polarization. Other efforts include detailed measurement of the stable spin direction at store and the commissioning of a machine protection relay system to prevent spurious firing of the RHIC abort kickers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST031  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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WEPOPT001 NICA Ion Collider and Plans of Its First Operations booster, collider, injection, electron 1819
 
  • E. Syresin, O.I. Brovko, A.V. Butenko, A.R. Galimov, E.V. Gorbachev, V. Kekelidze, H.G. Khodzhibagiyan, S.A. Kostromin, V.A. Lebedev, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, G.V. Trubnikov, A. Tuzikov
    JINR, Dubna, Moscow Region, Russia
 
  The Nuclotron-based Ion Collider fAcility (NICA) is under assembling in JINR. The NICA goals are providing of colliding beams for studies of hot and dense strongly interacting baryonic matter and spin physics. The heavy ion injection complex of Collider NICA consisting from following accelerators: new acting heavy ion linac HILAC with RFQ and IH DTL sections at energy 3.2 MeV/u, new acting superconducting Booster synchrotron at energy up 600 MeV/u, acting superconducting synchrotron Nuclotron at gold ion energy 3.9 GeV/n, will starts operation with first ion beams in beginning of 2022. The assembling of two Collider storage rings with two interaction points was done in December 2021. The status of acceleration complex NICA and plans of its first operation is under discussion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT001  
About • Received ※ 30 May 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022  
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WEPOPT002 Conception of High Intensive Polarized Proton Beam Formation in NICA Collider proton, collider, injection, acceleration 1822
 
  • E. Syresin, A.V. Butenko, S.A. Kostromin, O.S. Kozlov, I.N. Meshkov, A.O. Sidorin, G.V. Trubnikov, A. Tuzikov
    JINR, Dubna, Moscow Region, Russia
  • Y. Filatov
    MIPT, Dolgoprudniy, Moscow Region, Russia
  • S.D. Kolokolchikov, Y. Senichev
    RAS/INR, Moscow, Russia
  • A.M. Kondratenko, M.A. Kondratenko
    Science and Technique Laboratory Zaryad, Novosibirsk, Russia
  • N.V. Mityanina
    BINP SB RAS, Novosibirsk, Russia
  • P.R. Zenkevich
    ITEP, Moscow, Russia
 
  NICA (Nuclotron-based Ion Collider fAcility) is a new accelerator complex being assembled at JINR to search for the mixed phase of baryonic matter and to investigate the nature of nucleon/particle spin. The polarized proton beams will be operated at the energy range of 5-12.6 GeV, the beam intensity in each ring of 2.2x1013 and the luminosity of 1x1032 cm-2 s-1. The conception of formation of high intensive proton beams is discussed for two different schemes. In first scheme the protons are injected from Nuclotron to Collider at an energy of 2-2.5 GeV to provide the cooling and the storage at this energy and then they are accelerated up to energy of experiments. In the second scheme the cooling of protons is realized in one from accelerators of the injection chain and the protons are injected from Nuclotron to Collider at energy of experiments, where they are stored up required intensity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT002  
About • Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 12 June 2022
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WEPOPT003 Challenges of Low Energy Hadron Colliders collider, electron, emittance, operation 1825
 
  • G.V. Trubnikov, V.A. Lebedev
    JINR, Dubna, Moscow Region, Russia
  • A.V. Butenko, S.A. Kostromin, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, E. Syresin, A. Tuzikov
    JINR/VBLHEP, Dubna, Moscow region, Russia
 
  NICA collider complex is under construction at JINR. The initial configuration of the collider will perform collisions of fully stripped heavy ions, 209 Bi and others, for a study of phase transition in the quark-gluon plasma in the energy range 1/4.5 GeV/u per beam. Commissioning of the collider injection chain has been recently started. The complex includes 2 linacs, 2 Booster synchrotrons (Booster and Nuclotron to support the beam injection to the collider), and 2 collider rings of 503 m circumference. The design luminosity is ~1027 1/(cm*s) at 4.5 GeV/u. The heavy ions are generated in the ESIS-type ion source with intensity ~10 9 /pulse. Then they are accelerated into the linac and Booster and directed to stripping target. Next, fully stripped ions are accelerated in the Nuclotron and injected into Collider. The electron and stochastic cooling are used in each of the collider rings to support beam accumulation and to prevent the emittance growth due to intrabeam scattering. Three RF systems are used for longitudinal phase space manipulations. An achievement of design luminosity requires overcoming many technological and beam physics problems which are discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT003  
About • Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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WEPOPT009 Operational Scenario of First High Luminosity LHC Run operation, emittance, injection, sextupole 1846
 
  • R. Tomás García, G. Arduini, P. Baudrenghien, R. Bruce, O.S. Brüning, X. Buffat, R. Calaga, F. Cerutti, R. De Maria, J. Dilly, I. Efthymiopoulos, M. Giovannozzi, P.D. Hermes, G. Iadarola, O.R. Jones, S. Kostoglou, E.H. Maclean, N. Mounet, E. Métral, Y. Papaphilippou, S. Redaelli, G. Sterbini, H. Timko, F.F. Van der Veken, J. Wenninger, M. Zerlauth
    CERN, Meyrin, Switzerland
 
  A new scenario for the first operational run of the HL-LHC era (Run 4) has been recently developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL-LHC design. The operational scenario in terms of beam parameters and machine settings, as well as the different phases, are described here along with the impact of potential delays on key hardware components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT009  
About • Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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WEPOPT013 Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC beam-losses, simulation, collimation, collider 1862
 
  • C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
    CERN, Meyrin, Switzerland
 
  The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb3Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013  
About • Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022  
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WEPOPT014 The Effect of a Partially Depleted Halo on the Criticality and Detectability of Fast Failures in the HL-LHC beam-losses, simulation, collider, dipole 1866
 
  • C. Hernalsteens, C. Lannoy, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
    CERN, Meyrin, Switzerland
 
  In the High Luminosity LHC (HL-LHC) era, the bunch intensity will be increased to νm{2.2e11} protons, which is almost twice the nominal LHC intensity. The stored energy in each of the two beams will increase to §I{674}{MJ}. The HL-LHC will feature beams whose transverse halos are partially depleted by means of a hollow electron lens. The reduced stored energy in the beam tails will significantly change the development of losses caused by failures. This paper reports on beam tracking simulations evaluating the effect of a partially depleted halo on the criticality and detection of failures originating from the superconducting magnet protection systems. In addition, the effect of the transverse damper operating as a coherent excitation system leading to orbit excursions on a beam with a partially depleted halo is discussed. The results in terms of time-dependent beam losses are presented. The margins between the failure onset, its detection, and the time to reach critical loss levels, are discussed. The results are extrapolated to failure cases of different origins that induce similar beam loss dynamics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT014  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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WEPOPT017 First Optics Design for a Transverse Monochromatic Scheme for the Direct S-Channel Higgs Production at FCC-ee Collider optics, collider, positron, site 1878
 
  • H.P. Jiang
    Harbin Institute of Technology (HIT) , Harbin, People’s Republic of China
  • A. Faus-Golfe, Z.D. Zhang
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • K. Oide
    KEK, Ibaraki, Japan
  • Z.D. Zhang
    IHEP, Beijing, People’s Republic of China
  • Z.D. Zhang
    UCAS, Beijing, People’s Republic of China
  • F. Zimmermann
    CERN, Meyrin, Switzerland
 
  The FCC-ee collider baseline foresees four different energy operation modes: Z, WW, H(ZH) and ttbar. An optional fifth mode, called s-channel Higgs production mode, could allow the measurement of the electron Yukawa coupling, in dedicated runs at 125 GeV centre-of-mass energy, provided that the centre-of-mass energy spread, can be reduced by at least an order of magnitude (5-10 MeV). The use of a special collision technique: a monochromatization scheme is one way to accomplish it. There are several methods to implement a monochromatization scheme. One method, named transverse monochromatization scheme, consists of introducing a dispersion different from zero but opposite sign for the two colliding beams at the Interaction Point (IP); In this paper we will report about the first attempt to design a new optics to implement a transverse monochromatic scheme for the FCC-ee Higgs production totally compatible with the standard mode of operation without dispersion at the IP.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT017  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022
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WEPOPT032 Summary of the 3-year Beam Energy Scan II operation at RHIC electron, operation, space-charge, cavity 1908
 
  • C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
    BNL, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam Energy Scan phase II (BES-II) operation in the Relativistic Heavy Ion Collider (RHIC), aiming to explore the phase transition between quark-gluon plasma (QGP) and hadronic gas, exceeded the goal of a four-fold increase in the average luminosity over the range of five gold beam energies (9.8, 7.3, 5.75, 4.59 and 3.85 GeV/nucleon) compared to those achieved during Beam Energy Scan phase I (BES-I). We will present the achievements in BES-II together with a summary of the measures taken to improve RHIC performance in the presence of several beam dynamics effects, and details on improvements made during the operation at 3.85 GeV/nucleon in 2021.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT032  
About • Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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WEPOPT033 Report of RHIC Beam Operation in 2021 operation, target, electron, experiment 1912
 
  • C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
    BNL, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The first priority of RHIC operation in 2021 was the Au+Au collisions at 3.85 GeV/nucleon, which is the lowest energy to complete the 3-year Beam Energy Scan II physics program, with RF-based electron cooling. In addition, RHIC also operated for several other physics programs including fixed target experiments, O+O at 100 GeV/nucleon, Au+Au at 8.65 GeV/nucleon, and d+Au at 100 GeV/nucleon. This report presents the operational experience and the results from RHIC operation in 2021. With Au+Au collisions at 3.85 GeV/nucleon reported in a separate report, this paper focuses on the operation conditions for the other programs mentioned above.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT033  
About • Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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WEPOPT041 Strong-Strong Simulations of Coherent Beam-Beam Effects in the EIC electron, proton, simulation, resonance 1942
 
  • J. Qiang
    LBNL, Berkeley, California, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Luo, C. Montag, F.J. Willeke, D. Xu
    BNL, Upton, New York, USA
 
  The high luminosity electron ion collider (EIC) will provide great opportunities in nuclear physics study and is under active design. The coherent effects due to the beam-beam interaction of two colliding beams can cause beam size blow-up and degrade the luminosity in the EIC. In this paper, we report on the study of coherent beam-beam effects in the EIC design using self-consistent strong-strong simulations. These simulations show the coherent dipole and quadrupole mode instabilities in the tune working point scan and bunch intensity scan.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT041  
About • Received ※ 18 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 23 June 2022
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WEPOPT061 A Flexible Nonlinear Resonance Driving Term Based Correction Algorithm with Feed-Down optics, resonance, dipole, insertion 1999
 
  • J. Dilly, R. Tomás García
    CERN, Meyrin, Switzerland
 
  Funding: This work has been supported by the HiLumi Project and been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Re-search.
The optics in the insertion regions of the LHC and its upgrade project the High Luminosity LHC are very sensitive to local magnetic errors, due to the extremely high beta-functions. In collision optics, the non-zero closed orbit in the same region leads to a "feed-down" of high-order errors to lower orders, causing additional effects detrimental to beam lifetime. An extension to the well-established method for correcting these errors by locally suppressing resonance driving terms has been undertaken, not only taking this feed-down into account, but also adding the possibility of utilizing it such that the powering of higher-order correctors will compensate for lower order errors. Existing correction schemes have also operated on the assumption of (anti-)symmetric beta-functions of the optics in the two rings. This assumption can fail for a multitude of reasons, such as inherently asymmetric optics and unevenly distributed errors. In this respect, an extension of this correction scheme has been developed, removing the need for symmetry by operating on the two separate optics of the beams simultaneously.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT061  
About • Received ※ 07 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022  
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WEPOPT064 Simulations and Measurements of Luminosity at SuperKEKB simulation, resonance, experiment, impedance 2011
 
  • D. Zhou, Y. Funakoshi, K. Ohmi, Y. Ohnishi
    KEK, Ibaraki, Japan
  • Y. Zhang
    IHEP, Beijing, People’s Republic of China
 
  The interplay of beam-beam interaction, machine imperfections, and beam coupling impedance makes it difficult to predict the luminosity performance of SuperKEKB. Since 2020, the crab waist scheme was introduced to SuperKEKB to suppress beam-beam resonances. The coherent beam-beam head-tail instability and beam-beam driven synchro-betatron resonances due to large crossing angle can drive horizontal blowup, which cannot be suppressed by crab waist. The longitudinal impedance modulates the synchrotron motion and therefore affects beam-beam instability. In this paper, we compare simulations and measurements of luminosity and discuss the challenges and direction toward developing a predictable luminosity simulation model for SuperKEKB.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT064  
About • Received ※ 13 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
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WEPOTK034 LHC Beam Collimation During Extended β*-Levelling in Run 3 collimation, operation, experiment, optics 2138
 
  • F.F. Van der Veken, R. Bruce, M. Hostettler, D. Mirarchi, S. Redaelli
    CERN, Meyrin, Switzerland
 
  During the third operational Run of the Large Hadron Collider at CERN, starting in 2022, the bunch population will be increased to unprecedented levels requiring to deploy β*-levelling of the luminosity over a wide range of values to cope with the limitations imposed by event pile-up at the experiments and heat load on the triplets induced by collision debris. During this levelling, both beam optics and orbit change in various areas of the ring, in particular around the high-luminosity experiments, where several collimators are installed. This requires adapting the collimation system settings adequately, in particular for the tertiary collimators (TCTs) that protect the inner-triplet magnets. To this end, two strategies are considered: keeping collimators at fixed physical openings while shifting their centres following the beam orbit, or varying also the collimator openings. The latter strategy is planned when the larger optics range will be deployed. In this paper, we investigate several loss scenarios at the TCTs in different steps of the levelling, and present the proposed collimator settings during Run 3.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK034  
About • Received ※ 07 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022  
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WEPOTK050 The Report of Machine Studies Related to the Vertical Beam Size Blow-Up in SuperKEKB LER experiment, emittance, beam-beam-effects, coupling 2169
 
  • S. Terui, H. Fukuma, Y. Funakoshi, T. Ishibashi, T. Nakamura, K. Ohmi, Y. Ohnishi, M. Tobiyama, R. Ueki
    KEK, Ibaraki, Japan
 
  In the Low Energy Ring (LER) for positrons in the SuperKEKB, a vertical beam size blow-up was observed when the bunch current was approximately 1 mA. If a beam size blow-up occurs, the design luminosity cannot be achieved. Therefore, beam size blow-ups must be pre-vented. According to calculations, the bunch current threshold of the Transverse Mode Coupling instability (TMCI) is 2 mA or more, and the observed value is 50% or smaller. This vertical beam size blow-up cannot be explained by ordinary TMCI. This paper shows that by analyzing factors such as beam oscillation, the cause of the vertical beam size blow-up was determined. The study results showed that the vertical beam size blow-up in the LER was caused by the oscillations of the -1 mode.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK050  
About • Received ※ 17 May 2022 — Accepted ※ 22 June 2022 — Issue date ※ 25 June 2022  
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WEPOMS019 Beam-Beam Resonance Widths in the HL-LHC, and Reduction by Phasing of Interaction Points resonance, interaction-region, betatron, lattice 2280
 
  • Y.L. Gao, S.R. Koscielniak
    TRIUMF, Vancouver, Canada
 
  Beam-beam interactions are a limiting factor in the planned high luminosity (HL) upgrade to the Large Hadron Collider (HL-LHC). Over the two main interaction regions of the LHC, a particle experiences two head-on and over a hundred long-range beam-beam interactions which drive betatron resonances in the system. Each resonance line in the space of horizontal and vertical tunes has a finite (non-zero) lock-on width. If the particles tunes fall within this width, they will eventually lock on to the resonance and be driven to large amplitude. We show that it is possible to reduce the resonances widths of a given order by using specific values of the phase advance between interaction points. This paper presents the derivation of resonance width for the weak-strong beam-beam effect, as an extension of A.Chaos width formulae for magnetic sextupoles. (A Lie-algebraic approach is used to combine the effect of the individual beam-beam impulses.) The paper then studies the lock-on width arising from two interaction regions containing 140 beam-beam impulses, and shows the cancellation of specific resonances by relative phasing of interaction points in the HL-LHC lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS019  
About • Received ※ 27 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 22 June 2022
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THPOTK035 Thermo-Mechanical Modeling and Thermal Performance Analysis of Beam Vacuum Line Interconnections and Cold Warm Transitions in HL-LHC Long Straight Section Magnets cryogenics, radiation, vacuum, insertion 2839
 
  • J. Harray, C. Garion, V. Petit
    CERN, Meyrin, Switzerland
 
  The HL-LHC upgrade, aiming at increasing the LHC levelled luminosity by factor of five, relies on new superconducting magnets requiring a new beam vacuum system. Along with the challenges related to magnet design, the beam optic configuration exposes this new equipment to stringent conditions for vacuum and cryogenic performance. Both cold-warm transitions and magnet interconnections appear to be delicate components that are crucial for the thermal heat transfer between diverse subsystems. The proposed study aims at assessing the heat loads to the cryogenic system and the temperature fields in the vacuum system. A nonlinear static thermal analysis is first performed. A thermo-mechanical approach is developed to capture additional thermal resistance arising from contact between components and their behaviour during cool-down. The system is then studied under dynamic operations when beams are circulating and colliding. A thorough analysis of beam-induced heat loads under ultimate conditions highlights the different relevant contributions. Finally, the transient response of the systems is computed to assess thermal time constants.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK035  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 29 June 2022
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THPOMS057 Using Co-Moving Collisions in a Gear-Changing System to Measure Fusion Cross-Sections neutron, experiment, collider, ECR 3105
 
  • E.A. Nissen
    JLab, Newport News, Virginia, USA
 
  Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript.
In this work we look at a possible use for a system that collides beams moving in the same direction using a gear-changing synchronization method as a means of measuring low energy phenomena, such as fusion cross sections. Depending on the energies used this process will allow for interactions for any desired charge state of the target nuclei. Earlier concepts for low energy interactions to study focused on beams crossing at an angle to give the low energy interactions, as well as general investigations of comoving collisions. This proposal would use gear-changing, a method involving two different harmonic numbers of bunches in each collider ring, to have the same types of collisions, with a luminosity equal that of a head-on machine. In this work we detail the design considerations for such a machine, leveraging experimental experience with a co-moving, gear-changing system.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS057  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
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FRPLYGD1 Towards Efficient Particle Accelerators - A Review collider, cavity, cryogenics, radiation 3141
 
  • M. Seidel
    PSI, Villigen PSI, Switzerland
 
  Sustainability has become an important aspect of all human activities, and also for accelerator driven research infrastructures. For new facilities it is mandatory to optimize power consumption and overall sustainability. This presentation will give an overview of the power efficiency of accelerator concepts and relevant technologies. Conceptual aspects will be discussed for proton driver accelerators, light sources and particle colliders. Several accelerator technologies are particularly relevant for power efficiency. These are utilized across the various facility concepts and include superconducting RF and cryogenic systems, RF sources, energy efficient magnets, conventional cooling and heat recovery. Power efficiency has been a topic in the European programs EUCARD-2, ARIES and the ongoing I.FAST project and the documentation of these programs is a related source of information.  
slides icon Slides FRPLYGD1 [4.531 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRPLYGD1  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 29 June 2022
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